From b3a81b6c4fc6730ac49e20d789a93c0faabafc98 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Wed, 9 May 2018 12:12:15 -0700 Subject: [PATCH] HID: i2c-hid: check if device is there before really probing Git-commit: b3a81b6c4fc6730ac49e20d789a93c0faabafc98 Patch-mainline: v4.18-rc1 References: bsc#1051510 On many Chromebooks touch devices are multi-sourced; the components are electrically compatible and one can be freely swapped for another without changing the OS image or firmware. To avoid bunch of scary messages when device is not actually present in the system let's try testing basic communication with it and if there is no response terminate probe early with -ENXIO. Signed-off-by: Dmitry Torokhov Reviewed-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Acked-by: Takashi Iwai --- drivers/hid/i2c-hid/i2c-hid.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c index cf71c33ac2b2..c5ad918e36e3 100644 --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -1060,6 +1060,14 @@ static int i2c_hid_probe(struct i2c_client *client, pm_runtime_enable(&client->dev); device_enable_async_suspend(&client->dev); + /* Make sure there is something at this address */ + ret = i2c_smbus_read_byte(client); + if (ret < 0) { + dev_dbg(&client->dev, "nothing at this address: %d\n", ret); + ret = -ENXIO; + goto err_pm; + } + ret = i2c_hid_fetch_hid_descriptor(ihid); if (ret < 0) goto err_pm; -- 2.18.0